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From "Tim Armstrong (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5511: Add process start time to debug web page
Date Thu, 06 Jul 2017 21:59:31 GMT
Tim Armstrong has posted comments on this change.

Change subject: IMPALA-5511: Add process start time to debug web page
......................................................................


Patch Set 1:

(2 comments)

The overall approach seems good, but I had some concerns about the ReadProcStartTime() implementation.

http://gerrit.cloudera.org:8080/#/c/7363/1/be/src/util/process-state-info.cc
File be/src/util/process-state-info.cc:

Line 175:   const string& command = Substitute(
We're adding a runtime dependence on some additional command-line utilities, which seems brittle.
I'm not really sure which versions of these utilities support which arguments, etc. We really
want to avoid forking processes after start, since it can cause big spikes in virtual memory
usage, e.g. see IMPALA-2294

It seems like we can get the same info directly from stat(): http://pubs.opengroup.org/onlinepubs/009695399/functions/stat.html
then format it with strftime() or similar.


PS1, Line 176:  /proc/$0/
Is the ctime of this directory documented to be the process start time?

It looks like it matches on my system but if there's some official documentation it would
be good to reference.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I05ae2f80835b1b0e4bc3b38731778ba0871338a4
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Gabor Kaszab <gaborkaszab@cloudera.com>
Gerrit-Reviewer: Attila Jeges <attilaj@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Henry Robinson <henry@cloudera.com>
Gerrit-Reviewer: Laszlo Gaal <laszlo.gaal@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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